Apparatuses for automatic lubrication of cooperating surfaces at different mechanical mechanisms are well-known and they operate to provide, according to certain predetermined parameters, a lubricant film, which prevents direct metallic contact between the cooperating surfaces of the mechanism and which furthermore has for a purpose to protect against wear and corrosion.
The volume of lubricant needed for the lubrication in each specific case thereby is often decided from experience, and the lubricant automaton is set to discharge a desired quantity of lubricant.
In many applications grease is advantageous as lubricant and the automatons intended for such lubrication often consist of a valve, through which the lubricant is discharged, and a container connectable to the valve, which container has an internal piston driven by a spring or possibly via a diaphragm by means of an electrolytically generated driving gas.
Admittedly the valve and the container commonly are manufactured as separate units, but they generally have been assembled in such a manner, that the entire lubricant container with valve has been discarded when the grease in the container has been consumed.
For grease lubrication of rolling bearings it is essential that the bearing components are not supplied with more lubricant than what is absolutely necessary for obtaining a satisfactory lubrication, and this means very small quantities, as it hereby is obtained the operational temperature that is most advantageous for the bearing assembly.
If too much lubricant is fed into the bearing assembly, the milling operation resulting therefrom, will cause a considerable increase of the bearing temperature, thus giving an impaired lubrication and risk for early ageing of the grease.
SE-C-8702597-9 describes an apparatus for automatic grease lubrication of bearings, wherein the valve is equipped with an element adapted to sense the heat development at the bearing position and to cause a reduction of the lubricant feed, when a predetermined temperature level is exceeded. The heat sensing and heat actuatable element then is constituted by a memory metal spring, which acts to reduce and/or completely close the discharge opening of the valve, when the temperature at the bearing position raises above a certain level, and this apparatus gives a satisfactory feed-out quantity, well adapted to the heat development.
With the design of the apparatus hitherto used, the valve will be thrown away together with the emptied grease container, which means that grease lubrication with hitherto used equipment implies a resource waste, particularly at temperature governed valves of the above mentioned kind, as the material of the memory metal spring is rather expensive. Certainly the valve part and the container of the apparatus according to the above mentioned patent can be taken apart, but a parting of the valve body and the container and subsequent mounting of a new container means a circumstantial and particularly in small spaces troublesome work which is hardly rational.